Identification of CNS Sites Involved in the Cardiovascular and Renal Responses Elicited by Nociceptin/Orphanin FQ in Conscious Hypertensive Rats via c-Fos Immunocytochemistry.

Intracerebroventricular (ICV) administration of the opioid-like peptide agonist, nociceptin/Orphanin FQ (N/OFQ), produces a free water diuresis in addition to marked depressor effects on cardiovascular function and renal sympathetic nerve activity (RSNA). This study examined the changes in cFos expression in forebrain regions of angiotensin II high salt diet (ANGII) hypertensive rats following ICV administration of N/OFQ or saline vehicle. Protocol: 14 days prior to the experiment day, rats were implanted with an osmotic pump filled with angiotensin II and placed on a 2% high salt diet. At the day of the experiments, animals were placed in a metabolic cage and allowed to habituate for 3 hours. Following habituation, then two 15 minutes control periods, rats were than microinjected with either saline vehicle or nociceptin. Ninety minutes after the ICV injection, animals were perfused. Alternate sets of forebrain sections were processed for cFos using a commercially available antibody (Oncogene AB-5). Resul...